TRENTON, N.J. – Prominent Republicans leapt to GOP Gov. Chris Christie’s defence on Sunday, insisting that an ongoing traffic scandal wouldn’t ruin any presidential ambitions, while Democrats say it’s difficult to believe such a hands-on manager knew nothing about a plan by a top aide to close lanes at a bridge into New York City.

Politicians from both sides of the aisle took to the Sunday talk shows to debate the fallout from the traffic jams near the George Washington Bridge in September and any role Christie may have played. Documents show Christie’s aides appeared to engineer lane closures at the heavily travelled bridge to punish a Democratic mayor who failed to endorse his re-election bid.

Republican National Committee Chairman Reince Priebus told NBC’s “Meet the Press” Christie could move past the scandal and still win support from primary voters in the 2016 presidential race.

He said Christie demonstrated leadership by holding a lengthy news conference Thursday to apologize for the scandal, the most serious challenge to his political career, and to disavow any knowledge of its planning.

“America’s a forgiving people, but they’re forgiving when you take ownership, you admit mistakes, you take corrective action, and that’s what Chris Christie showed,” Priebus said.

Christie said he was “embarrassed and humiliated” by the conduct of some of his staff, including top aide Bridget Anne Kelly, whom he fired after learning she gave the go-ahead to close the lanes. Christie said he was “blindsided” by the revelations, which he said he discovered when subpoenaed emails were released last week.

John Wisniewski, a New Jersey Democrat leading the legislative investigation into the traffic jams, told CBS’ “Face the Nation” there’s no evidence Christie was directly involved in the traffic tie-up. But he said the governor didn’t have to know about the lane closures for them to be a crime.

“When you use the George Washington Bridge for what the emails show to be a political payback, that amounts to using public property for a private purpose or for a political purpose, and that’s not legal,” Wisniewski said.

Former New York City Mayor Rudy Giuliani, a Republican, said on ABC’s “This Week” he found Christie’s explanation “pretty darn credible” that he didn’t know what members of his inner circle were up to while he was running for re-election.

“He was in campaign mode,” Giuliani said. “You miss a lot of things. You’re not paying as much attention.”

Mark Sokolich, the Democratic mayor of Fort Lee whose town was clogged with traffic, said he wanted to believe Christie’s staffers acted without his knowledge but was having a tough time buying it.

“Anything his name was even remotely involved in, he was involved in,” said Sokolich, who met with Christie on Thursday, when the governor travelled to Fort Lee to apologize personally. The traffic delayed emergency vehicles and school buses and infuriated commuters in his town.

Sokolich, who had initially urged the governor to stay away, said afterward that the meeting was productive.

“I’m taking him at his word,” he said Sunday. “There’s just a lot of stuff there, though.”

Fox News Sunday political analyst Juan Williams said the scandal gives wider berth to conservatives already wary of Christie for signing a bill lowering tuition costs for students in the country illegally and embracing President Barack Obama after Superstorm Sandy.

“Right now, it looks like there’s a blockage on the long bridge to 2016 for Chris Christie,” Williams said.